Polyamide resins are a material which is used for wide applications including fibers, engineering plastics, and the like; however, it is known that the polyamide resins are easily hydrolyzed in an acidic medium.
In order to improve hydrolysis resistance or the like of polyamide resins, a polyamide resin composition in which a polyamide resin is blended with an aliphatic carbodiimide compound is known (Patent Document 1). Though such a polyamide resin composition has such properties that it is excellent in terms of hydrolysis resistance, there is a concern that it is insufficient in terms of flexibility and impact resistance.
Then, as a thermoplastic resin composition which is excellent in terms of barrier properties and mechanical properties such as strength, impact resistance, elongation, etc., a thermoplastic resin composition containing a polyamide resin (A) which is composed of a polyamide resin (a-1) in which 70% by mole or more of a diamine constituent unit thereof is derived from m-xylylenediamine, and 70% by mole or more of a dicarboxylic acid constituent unit is derived from an α,ω-linear aliphatic dicarboxylic acid having from 4 to 20 carbon atoms and nylon 11 and/or nylon 12 (a-2); and a carbodiimide compound (B) having two or more carbodiimide groups in a molecule thereof is known (Patent Document 2).